(1) Field of the Invention
The present invention relates to porous aluminosilicate compositions which have a unique structure which are stable at high temperatures and under hydrothermal conditions. In particular, the present invention relates to a process for producing the porous aluminosilicate composition which uses a zeolite seed with a structure directing agent. Further still, the present invention relates to novel cracking catalysts for oil and other organic molecules. The present invention thus provides for the assembly of ultrastable porous aluminosilicates with hexagonal, cubic, wormhole or foam framework structures that do not suffer from the undesirable extensive de-alumination and steam instability of conventional aluminosilicate compositions.
(2) Description of Related Art
All previously reported aluminosilicate mesostructures, as prepared by either direct or post synthesis alumination, result in the extensive de-alumination of the framework upon calcination (Ryoo, R., et al., Chem. Commun. 2225 (1997); and Luan, Z. H., et al., J. Phys. Chem. 99 10590 (1995)). This undesired property has been attributed to the hydrolysis of the framework Al by steam generated in the calcination process (Corma, A., et al., J. Catal. 148 569 (1994); and Luan, Z. H., et al., J. Phys. Chem. 99 10590 (1995)). Regardless of the mechanism responsible for the de-alumination process, the acid catalytic properties of these materials for organic chemical conversions is greatly compromised. Moreover, all previously reported aluminosilicate mesostructures completely lose their framework mesoporosity when exposed to steam at the temperatures normally encountered in the processing of petroleum catalysts.
Soon after the discovery of mesoporous MCM-41 molecular sieves (Beck, J. S., et al., J. Am. Chem. Soc. 114 10834 (1992)), it was found that the incorporation of aluminum into the framework introduced mild acidic functionality, but the long range order and tetrahedral siting of the aluminum was compromised (Chen, C-Y., et al., Microporous Mater. 2 17 (1993); Borade, R. B., et al., Catal. Lett 31 267 (1994); Luan, Z. H., et al., J. Phys. Chem. 99 10590 (1995)), especially at intended aluminum loadings above about 8 mol %. Mild acidity and loss of structural integrity, together with poor steam stability under regeneration conditions made hexagonal Al-MCM-41 compositions unattractive candidates for the processing of high molecular weight petroleum fractions. More recently, important advances have been made in improving the structural integrity of Al-MCM-41 through direct assembly (Janicke, M. T., et al. , Chem. Mater. 11 1342 (1999)) and post synthesis modification methods (Hamdan, H., et al., J. Chem. Soc. Faraday Trans 92 2311 (1996); Mokaya, R., et al., Chem. Commun. 2185 (1997); Ryoo, R., et al., J. Chem. Commun. 2225 (1997); and Ryoo, R., et al., Chem. Mater. 9 1607 (1998)). However, the low acidity and poor steam stability still limit potential applications in petroleum refining (Corma, A., Chem. Rev. 2373 (1997)).
There is thus a need for improved aluminosilicate compositions, both mesostructured with larger pore sizes that are stable, particularly in the presence of steam. In particular, the present invention relates to aluminosilicates that have stable framework structures.
The present invention relates to a porous structured aluminosilicate composition which comprises:
a framework of linked tetrahedral SiO4 and AlO4 units, the framework defining pores and having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 2 and 100 nm, and wherein the composition retains at least 50% of an initial framework pore volume after exposure to 20 volume % steam at 800xc2x0 C. for two hours.
The present invention also relates to a porous structured aluminosilicate composition which comprises a framework of linked SiO4 and AlO4 units, the framework defining pores and having a Si to Al molar ratio of about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak between 2 and 100 nm, and wherein the composition retains at least 75% of an initial framework pore volume after exposure to 20 volume percent steam at 600xc2x0 C. for four hours.
The present invention also relates to a porous structured aluminosilicate composition which comprises:
a framework of linked tetrahedral SiO4 and AlO4 units, the framework defining pores having an organic surfactant in the pores and having a Si to Al molar ratio of between 1000 to 1 and 1 to 1 and having at least one X-ray defraction peak corresponding to a basal spacing between about 2 and 100 nm and wherein the composition is derived from an organic surfactant, an optional co-surfactant, and preformed zeolite seeds.
The present invention also relates to a process for forming a porous aluminosilicate composition which comprises:
(a) providing protozeolitic aluminosilicate seeds selected from the group consisting of an aqueous solution, gel, suspension wetted powder and mixtures thereof;
(b) reacting in a mixture the seeds in an aqueous medium with an organic surfactant;
(c) aging the mixture of step (b) at a temperature between 25xc2x0 and 200xc2x0 C. to obtain a precipitate of the composition; and
(d) separating the composition from the mixture of step (c).
The present invention also relates to a structured aluminosilicate composition which comprises:
a framework of linked tetrahedral SiO4 and AlO4 units, the framework defining mesopores having a surfactant and optionally a co-surfactant in the mesopores, having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 2.0 and 100 nm, and which when calcined retains at least 50% of an initial framework pore volume after exposure to 20 volume percent steam at 800xc2x0 C. for two hours.
The present invention further relates to a porous aluminosilicate composition which comprises: a framework of tetrahedral linked SiO4 and AlO4 units, the framework defining mesopores having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 2.0 and 100 nm, wherein a BET surface area is between 200 and 1400 m2 per gram, wherein an average pore size of the framework is between about 1.0 and 100 nm, and wherein a pore volume of the framework is between about 0.1 and 3.5 cm3 per gram, and which retains at least 50% of an initial framework pore volume after exposure to 20 volume percent steam at 800xc2x0 C. for two hours.
The present invention further relates to a hybrid porous aluminosilicate-carbon composition which comprises: a framework of linked tetrahedral SiO4 and AlO4 units, the framework defining mesopores having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1 and between 0.01 and 10 wt % carbon embedded in the mesopores, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 2.0 and 100 nm, wherein a BET surface area is between 200 and 1400 m2 per gram, wherein an average pore size of the framework is between about 1.0 and 100 nm, and wherein a pore volume of the framework is between about 0.1 and 3.5 cm3 per gram, and which retains at least 50% of an initial framework pore volume after exposure to 20 volume percent steam at 800xc2x0 C. for two hours.
The present invention further relates to a process for forming the mesoporous aluminosilicate composition which comprises:
(a) reacting a sodium silicate solution at basic pH with a sodium aluminate solution at an aluminum to silicon ratio between about 1000 to 1 and 1 to 1 and aging the mixture at 25 to 200xc2x0 C. for periods of up to 48 hours to form zeolite seeds;
(b) reacting the resultant mixture with a surfactant and optionally a co-surfactant;
(c) acidifying the mixture obtained from (b) with a protonic acid to obtain a mixture with an OHxe2x88x92/(Si+Al) ratio in the range of 0.10 to 10;
(d) aging the mixture from step (c) at a temperature between 20 and 200xc2x0 C. to obtain a precipitate of the composition; and
(e) separating the composition from mixture of step (d).
The present invention further relates to a process for forming the mesoporous aluminosilicate composition which comprises:
(a) providing zeolite seeds as an aqueous solution, gel, suspension, wet powder, or combination thereof;
(b) reacting the zeolite seeds in the aqueous medium with a surfactant wherein the solution has an OHxe2x88x92/(Si+Al) ratio in the range of 0.10 to 10;
(c) aging the mixture from step (b) at a temperature between 20 and 200xc2x0 C. to obtain a precipitate of the composition; and
(d) separating the composition from the mixture of step (c).
The present invention further relates to a catalyst useful for a fluidized bed catalytic cracking (FCC) or hydrocracking of an organic molecule which comprises:
(a) a mesoporous aluminosilicate composition which comprises a framework of linked tetrahedral SiO4 and AlO4 units, the framework defining mesopores having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 2.0 nm and 100 nm, wherein a BET surface area is between 200 and 1400 m2 per gram, wherein an average pore size of the framework is between about 1.0 and 100 nm, and wherein a pore volume of the framework is between about 0.1 and 3.5 cm3 per gram, and which retains at least 50% of an initial framework pore volume after exposure to 20 volume percent steam at 800xc2x0 C. for two hours; and
(b) a binder for the aluminosilicate composition.
The present invention further relates to a catalyst useful for fluidized bed catalytic cracking (FCC) or hydrocracking of an organic molecule which comprises:
(a) a mesoporous aluminosilicate-carbon composition which comprises a framework of linked tetrahedral SiO4 and AlO4 units, the framework defining mesopores having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1 and between 0.01 and 10 wt % carbon embedded in the mesopores, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 2.0 and 100 nm, wherein a BET surface area is between 200 and 1400 m2 per gram, wherein an average pore size of the framework is between about 1.0 and 100 nm, and wherein a pore volume of the framework is between about 0.1 and 3.5 cm3 per gram, wherein the carbon content is between 0.01 and 10% by weight, and which retains at least 50% of an initial framework pore volume after exposure to 20 volume percent steam at 800xc2x0 C. for two hours; and
(b) a binder for the aluminosilicate-carbon composition.
The present invention further relates to a process for catalytic reaction of an organic molecule into lower molecular weight components, which comprises:
(a) providing in a reactor a catalytic cracking catalyst which comprises: a mesoporous aluminosilicate composition which comprises a framework of linked tetrahedral SiO4 and AlO4 units, the framework defining mesopores having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 2.0 and 100 nm, wherein a BET surface area is between 200 and 1400 m2 per gram, wherein an average pore size of the framework is between about 1.0 and 100 nm, and wherein a pore volume of the framework is between about 0.1 and 3.5 cm3 per gram; and a binder for the aluminosilicate composition, and which retains at least 50% of an initial framework pore volume after exposure to 20 volume percent steam at 800xc2x0 C. for two hours; and
(b) introducing the organic molecule onto the catalyst at temperatures and pressures which cause the reaction of the organic molecule.
The present invention further relates to a process for catalytic reaction of an organic molecule into lower molecular weight components, which comprises:
(a) providing in a reactor a catalytic cracking catalyst which comprises: a mesoporous aluminosilicate-carbon composition which comprises: a framework of tetrahedral linked SiO4 and AlO4 units, the framework defining mesopores having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1 and between 0.01 and 10 wt % carbon embedded in the mesopores, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 2.0 and 100 nm, wherein a BET surface area is between 200 and 1400 m2 per gram, wherein an average pore size of the framework is between about 1.0 and 100 nm, and wherein a pore volume of the framework is between about 0.1 and 3.5 cm3 per gram; and a binder for the aluminosilicate-carbon composition, and which retains at least 50% of an initial framework pore volume after exposure to 20 volume percent steam at 800xc2x0 C. for two hours; and
(b) introducing the organic molecule onto the catalyst at temperatures and pressures which cause the reaction of the organic molecule.
The present invention further relates to a catalyst useful for a fluidized bed catalytic cracking (FCC) or hydrocracking of an organic molecule which comprises:
(a) a porous structured aluminosilicate composition which comprises:
a framework of linked tetrahedral SiO4 and AlO4 units, the framework defining pores and having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 1 and 100 nm, and wherein the composition retains at least 50% of the initial framework pore volume after exposure to 20 volume % steam at 800xc2x0 C. for two hours; and
(b) a binder for the aluminosilicate composition.
The present invention further relates to a process for reaction of an organic molecule into lower molecular weight components which comprises:
(a) providing a porous structured aluminosilicate composition which comprises:
a framework of linked tetrahedral SiO4 and AlO4 units, the framework defining pores and having an Si to Al molar ratio of between about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 1 and 100 nm, and wherein the composition retains 50% of the initial framework pore volume upon exposure to 20 volume percent steam at 800xc2x0 C. for two hours; and
(b) introducing the organic molecule onto the catalyst at temperatures and pressures which cause the reaction of the organic molecule.
The present invention also relates to a catalyzed organic reaction, the improvement which comprises:
conducting the reaction with a catalyst which is selected from the group consisting of a porous structured aluminosilicate, gallosilicate, titanosilicate and mixtures thereof which catalyst comprises: a framework of linked tetrahedral SiO4 and AlO4, GaO4 or TiO4 units, the framework defining pores and having an Si to combined Ga, Ti and Al molar ratio of between about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 2 and 100 nm, and wherein the composition retains at least 50% of initial framework pore volume after exposure to 20 volume % steam at 600xc2x0 C. for four hours.
The present invention also relates to a porous structured silicate composition which comprises:
a framework of linked tetrahedral SiO4 and units selected from the group consisting of AlO4 units, GaO4 units, TiO4 units and mixed units, the framework defining pores and having an Si to combined Ga, Ti and Al molar ratio of between about 1000 to 1 and 1 to 1, and having at least one X-ray diffraction peak corresponding to a basal spacing between about 1 and 100 nm, and wherein the composition retains at least 50% of the initial framework pore volume after exposure to 20 volume percent steam at 600xc2x0 C. for four hours.
The compositions of the present invention can be used for hydroprocessing of petroleum, especially hydrocracking processes wherein petroleum fractions, for example, distillates or resid fractions, are cracked to lower molecular weight fractions of useful hydrocarbons in the presence of hydrogen gas. The beds for the catalytic cracking can be fluidized. Usually the beds for hydrocracking are fixed.